Wireless vehicle detection system and associated methods having enhanced response time

ABSTRACT

Embodiments of the invention include a wireless vehicle detection systems and associated methods with extended range and battery life. The wireless vehicle detection system can include a plurality of sensor pods in communication with an access point without repeaters. Embodiments of the sensor pod can include a vehicle detector controller adapted to determine the presence of vehicles and a communication controller connected to the vehicle detector and adapted to transmit data 300 feet or more to an access point, which in turns communicates with the base station. To extend the battery life of the sensor pod, the sensor pod can be adapted to detect received communication signal strength and adjust transmitting power based upon said strength to thereby conserve power. Embodiments of the sensor pod can also include a battery connected in parallel to an HLC capacitor to further extend the life of the battery.

RELATED APPLICATIONS

This application is related to and claims priority and benefit toprovisional application No. 61/770,606, titled, “Wireless VehicleDetection System and Associated Methods Having Enhanced Response Time,”filed on Feb. 28, 2013; application No. 61/770,789, titled, “WirelessVehicle Detector Aggregator and Interface to Controller and AssociatedMethods,” filed on Feb. 28, 2013; and application No. 61/770,951, titled“Wireless Vehicle Detection System, Sensor Pods, and AssociatedMethods,” filed on Feb. 28, 2013, each of which is incorporated hereinby reference in its entirety. This application is also related to thenon-provisional U.S. patent application filed on the same day as thisapplication, titled “Wireless Vehicle Detector Aggregator and Interfaceto Controller and Associated Methods,” which is also incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to vehicle detection systems and, moreparticularly, wireless vehicle detection systems and methods associatedwith detecting vehicles on roadways or other travel surfaces.

BACKGROUND

Currently offered wireless detection systems are cumbersome andexpensive, with various components communicating over the same RFchannel, and with a relatively short RF communication range. An averagesized traffic intersection, for example, requires multiple repeaters tocommunicate to the various in-road wireless vehicle sensors. Thisconfiguration makes the entire system expensive to install, therebyreducing the opportunities for using vehicle detection technology.

Moreover, current wireless vehicle detection systems use wiredcommunication from the access point to the controller cabinet. Inside ofthe controller cabinet, connections are made through a detector rackusing cables and multiple printed circuit boards; usually two or fourper card. Connecting large numbers of detector signals can be cumbersomeand costly.

SUMMARY OF INVENTION

Applicants recognized problems associate with current vehicle detectionsystems and methods including needs for lower cost, more reliable andeasy to install, i.e. minimum lane closure time during installation,among others. Embodiments of wireless vehicle detection systems andassociated methods of the present invention address these problems witheloquent solutions including, for example, a flexible vehicle detectionsystem with a simplified architecture. Embodiments of the wirelessvehicle detection systems reduce if not eliminate the need forrepeaters. Embodiments of the present invention, for example, providesystems and methods having sensors able to communicate over longerdistances, which allow repeaters to be eliminated for intersections, ifdesired, and still maintain relatively long, e.g., 10 years, battery orother power source life. Embodiments of the invention are less-costlyand more accurate and robust than current systems.

Embodiments can include one or more wireless sensor pods having a uniqueantenna with its radiating element close to the surface, the antennahaving a radiation pattern and orientation that allows the sensor totransmit signals more than approximately 700 feet, for example, to anaccess point. To conserve power usage, an embodiment of the sensor podis adapted to detect received communication signal strength, andoperationally adapted to adjust transmitting power based upon saidstrength. According to embodiments of the invention, the sensor pod caninclude, for example, a vehicle detector controller adapted to determinethe presence of one or more vehicles, and a communication controllerconnected to the vehicle detector and adapted to transmit data 700 feetor more away from the sensor pod, the data relating to the detectedpresence of one or more vehicles. The vehicle detector controller andthe communication controller each having separate clock cycles andseparately controlled sleep cycles for drawing power according to anembodiment of the sensor pod. The sensor pod can further include, forexample, a battery sufficiently large to support transmit powersufficient to achieve a transmission range of 300 feet or more and ahybrid layer capacitor connected in parallel electrically to the batteryto protect the battery from degradation at transmit power levels tothereby extend the life of the battery. To fit in the enclosure of thesensor pod, embodiments of the invention include a low profile antennaof the pod positioned in a substantially horizontal orientation whenpositioned inside an enclosure of the sensor pod and near a top end ofthe enclosure when the sensor pod is positioned in or below the surfaceof the road, the antenna is adapted to allow for and support a 902-928MHz ISM radio frequency band. The low profile antenna can also have anantenna housing having a hollow interior to allow communicationcircuitry components to be mounted at least partially inside the antennahousing thereby decreasing vertical space requirements inside of theenclosure of the sensor pod according to an embodiment of the invention.

Embodiments of the wireless vehicle detection system can furtherinclude, for example, a base station adapted to provide processing andstorage for the wireless vehicle detection system and an access pointadapted to communicate with the base station wireless at a communicationfrequency of approximately 2.4 GHz or via one or more wires, and furtheradapted to communicate with the one or more sensor pods at acommunication frequency of approximately 902-928 Mhz.

Embodiments of the invention can be used for a plurality of trafficzones, each zone including, for example, an access point incommunication with a sensor pod. Embodiments of the access point caninclude, for example, a sensor state aggregator module adapted tomaintain current detect status of the one or more sensor pods in arespective zone, the sensor state aggregator comprising a set ofinstructions that causes the access point, when executed by a accesspoint controller, to perform the operation of generating a first sensorstate array, each of the one or more sensor pods in the respective zonehaving an entry in the sensor state array. The operations according toan embodiment of the invention can further include, for example,updating the sensor state array responsive to receiving one or moresignals from the one or more sensor pods in the respective zone, the oneor more signals including current detect status of the one or moresensor pods. The access point is adapted to communicate with the basestation. Accordingly, embodiments of the sensor state aggregator moduleassociated with the access point can further include, communicating, tothe base station, an output message indicating a time stamp and eventtrigger details responsive to receiving an individual status messagefrom one or more of the sensor pods responsive to an event trigger, andcommunicating the updated sensor state array indicating current detectstatus of the one or more sensor pods upon demand or after apredetermined time period.

Embodiments of the base station can be adapted to provide dataprocessing and storage for the wireless vehicle detection system. Thebase station can include, for example, a base station controller, a businterface unit emulator, and a traffic detector aggregator moduleadapted to aggregate data from the plurality of access points so that auser can configure and monitor the wireless vehicle detection system. Anembodiment of the traffic detector aggregator module comprises a set ofinstructions that causes the base station, when executed by the basestation controller for example, to perform the operation of generating asecond sensor state array, each of the one or more sensor pods in all ofthe zones having an entry in the sensor state array. The operations canfurther include, for example, updating the second sensor state arrayresponsive to receiving updated sensor state array from one of theplurality of access points, generating a vehicle detector array, thevehicle detector array comprising information indicating a physicaldetector input for each of the zones of and time stamps of eventtriggers, and updating the vehicle detector array responsive toreceiving the output message from one of the plurality of access points.

Embodiments of a sensor pod provide extended communication range toallow an access point to talk to all or almost all sensors in anintersection without the need of repeaters. Embodiments of a wirelessvehicle detection system provide a relatively low cost, easy to installand flexible wireless vehicle detection system and associated methods.

Embodiments of aggregators, controllers, systems and methods of thepresent invention, for example, aggregate sensor detect status at theaccess point and relay that information to a base station periodicallyby wire or wirelessly. Inside of the controller cabinet assembly, a basestation unit aggregates and combines sensor status data into detectoroutput data according to an embodiment of the invention. Additionally,the base station controller and SDLC interface circuitry can emulate businterface units such that, for example, up to 128 detector outputs canbe provided through a single SDLC cable and without need for anyadditional printed circuit boards or their associated special cables.

Embodiments of the system can include, for example, a plurality ofaccess points adapted to communicate with one or more sensor pods in aplurality of zones, each zone having at least one sensor pod incommunication with at least one of the plurality of access points. Anembodiment can include, for example, a plurality of access points in atraffic intersection. Embodiments of the access point can include, forexample, an access point controller including a sensor state aggregatormodule adapted to maintain current detect status sensor pods in a zone.The sensor state aggregator, according to an embodiment of theinvention, can cause the access point to perform the operations ofgenerating a first sensor state array, each of the one or more sensorpods in the respective zone having an entry in the sensor state arrayand updating the sensor state array responsive to receiving one or moresignals from the one or more sensor pods in the respective zone, the oneor more signals including current detect status of the one or moresensor pods. Embodiments of the invention can cause the access point toperform the operations of communicating an output message indicating atime stamp and event trigger details responsive to receiving anindividual status message from one or more of the sensor pods responsiveto an event trigger, and communicating the updated sensor state arrayindicating current detect status of the one or more sensor pods upondemand or after a predetermined time period.

Embodiments of the system can further include, for example, a basestation adapted to provide data processing and storage for the wirelessvehicle detection system. The base station can comprise a base stationcontroller and one or more non-transitory memories encoded with one ormore computer programs operable by the base station controller. The oneor more computer programs, according to an embodiment of the invention,can include a traffic detector aggregator module adapted to aggregatedata from the plurality of access points so that a user can configureand monitor the wireless vehicle detection system. The traffic detectoraggregator module comprising, for example, a set of instructions thatcauses the base station, when executed by the base station controller,to perform the operation of generating a second sensor state array, eachof the one or more sensor pods in all of the zones having an entry inthe sensor state array, and updating the second sensor state arrayresponsive to receiving updated sensor state array from one of theplurality of access points. The operations adapted to be performed bythe base station can further include, for example, generating a vehicledetector array, the vehicle detector array comprising informationindicating a physical detector input for each of the zones of and timestamps of event triggers and updating the vehicle detector arrayresponsive to receiving the output message from one of the plurality ofaccess points. Embodiments of the base station can further include, forexample, one or more bus interface unit (BIU) emulators adapted to be incommunication with a SDLC Interface, the SDLC interface being incommunication with a traffic controller so that the BIU emulator isresponsive to the traffic controller

BRIEF DESCRIPTION OF DRAWINGS

So that the manner in which the features and advantages of theinvention, as well as others, which will become apparent, may beunderstood in more detail, a more particular description of theinvention briefly summarized above may be had by reference to theembodiments thereof, which are illustrated in the appended drawings,which form a part of this specification. It is to be noted, however,that the drawings illustrate only various embodiments of the inventionand are therefore not to be considered limiting of the invention'sscope, which may include other effective embodiments as well.

FIG. 1 illustrates an environmental view of the wireless vehicledetection system according to an embodiment of the invention.

FIG. 2 illustrates a schematic diagram of the wireless vehicle detectionsystem according to an embodiment of the invention.

FIG. 3 illustrates an environmental view of a sensor pod installed in aroad surface according to an embodiment of the invention.

FIG. 4 illustrates a schematic block diagram of a sensor pod accordingto an embodiment of the invention.

FIG. 5 illustrates a schematic block diagram of a vehicle detectorcontroller according to an embodiment of the invention.

FIG. 6 illustrates a schematic block diagram of a communicationcontroller according to an embodiment of the invention.

FIG. 7 illustrates a schematic block diagram of an access pointaccording to an embodiment of the invention.

FIG. 8 illustrates the access point according to an embodiment of theinvention.

FIG. 9 illustrates the access point housing according to an embodimentof the invention.

FIG. 10 illustrates the access point according to an embodiment of theinvention.

FIG. 11 illustrates a panel antenna according to an embodiment of theinvention.

FIG. 12 illustrates an omnidirectional antenna according to anembodiment of the invention.

FIG. 13 illustrates flow chart depicting operation of methods associatedwith a wireless detection system according to an embodiment of theinvention.

FIG. 14 is a flow chart depicting operation of methods for asynchronousevents associated with a wireless vehicle detection system according toan embodiment of the present invention.

FIG. 15 illustrates a block diagram of the base station according to anembodiment of the invention.

FIG. 16 illustrates a block diagram of the sensor state aggregatoraccording to an embodiment of the invention.

FIG. 17 illustrates a block diagram of the traffic detector aggregatoraccording to an embodiment of the invention.

FIG. 18 illustrates the sensor state array according to an embodiment ofthe invention.

FIG. 19 illustrates the vehicle detector array according to anembodiment of the invention.

FIG. 20 illustrates a graphical user interface to manage the wirelessvehicle detection system according to an embodiment of the invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theillustrated embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.

Embodiments of the present invention include a wireless vehicledetection system having an extended range that eliminates or at leastreduces the number of repeaters needed. An average sized trafficintersection using current vehicle detection systems requires multiplerepeaters to communicate with current vehicle detection sensors.Embodiments of the present invention include, for example, one or morewireless sensor pods having extended range and battery life that enablesthe wireless vehicle detection system according to embodiments of thepresent invention to communicate over long distances for a number ofyears (e.g., five years or more) without repeaters. Embodiments of theinvention provide, for example, enhanced response times and lowerlatency by providing sensor pods that are adapted to communicatedirectly with access points over long distances (e.g., 300 feet ormore). Embodiments of the present invention provide a cost-effectivewireless detection system for a broad range of transportation needs.

As illustrated in FIG. 1, the vehicle detection system 100 can include aplurality of wireless sensor pods 200 adapted to detect the presence ofa vehicle and positioned in or below the road surface, an access point300 mounted to a traffic pole and adapted to receive data sensed by thesensor pods, and a base station 400 positioned within a trafficcontroller cabinet 600 to provide data signal processing.

As illustrated in FIG. 2, embodiments of vehicle detection system 100can include a plurality of access points 300 each adapted to communicatewith one or more sensor pods 200 in a traffic region zone. According toan embodiment of present invention, each zone includes at least onesensor pod 200 in communication with one of the plurality of accesspoints 300. Each access point 300 is adapted to communicate with up to130 sensor pods 200 in a zone according to an embodiment of the presentinvention. The base station 400 can be adapted to provide dataprocessing and storage for the wireless vehicle detection system and beconnected to a WAN or LAN network and a traffic controller 402 asunderstood by those skilled in the art. Embodiments of the wirelessvehicle detection system 100 enable a user to configure or monitor thevehicle detection system 100 using a remote device 407.

FIG. 3 illustrates a sensor pod 200 installed below a road surface.Embodiments of the sensor pod 200 can include, for example, an antenna204 adapted to communicate with the access point 300, a PC board 211where one or more electronic hardware components attach thereto, abattery 206, and a hybrid layer capacitor (HLC) 208 connected inparallel electrically to the battery 206 to protect the battery fromdegradation as understood by those skilled in the art.

Embodiment of the present invention provides for simple installation ofthe sensor pods 200 with minimal road closure duration. A small hole canbe cut in the road using, for example, a diamond tipped drill bit orother suitable drilling or cutting apparatus as understood by thoseskilled in the art. According to an example embodiment, the hole isapproximately two and half inches deep and four to four and half inchesin diameter. After the hole is drilled, a shop vacuum can be used toremove debris and a propane torch can be used to dry out the hole beforethe adhesive is used. Epoxy or adhesive is placed in the bottom of thehole and the sensor pod is positioned inside the hole and in theadhesive. According to some embodiments, the remaining void of the holeis filled with adhesive or sealant and topped with a sealant 202 that isleveled with the surface of the road. A top end of the enclosure of thesensor pod 200 can be positioned such that the top surface is near theroadway surface. This allows, as illustrated in FIG. 3 for example, forthe antenna 204 positioned inside the enclosure of the sensor pod to benear the surface of the road. According to an example embodiment, thesensor pod 200 is positioned approximately ⅜ of an inch from the roadwaysurface. The radiation pattern of the antenna enables efficientcommunication with the access point 300 when the antenna 204 ispositioned inside the enclosure of the pod and installed below thesurface of the road according to an embodiment of the invention.

As illustrated in FIG. 4, embodiments of the sensor pod can include avehicle detector controller 240 adapted to detect the presence of avehicle and a communication controller 220 adapted to communicate datarelating to the presence of one or more vehicles to the access point300. The vehicle detector controller 240 and the communicationcontroller 220 can be connected by a serial communication link 241 suchas SPI, UART, or other communication links as understood by thoseskilled in the art. One or more program lines 242 can also be used toconnect or control the two controllers 220, 240. According to anembodiment of the present invention, the vehicle detector controller 240and the communication controller 220 each have separate clock cycles andseparately controlled sleep cycles for drawing power. The battery 206 ofthe sensor pod is large enough to support transmit power sufficient toachieve at least 300 feet or more. In an example embodiment, the battery206 is a lithium thionylchloride, compact D size and is capable ofstoring a substantial charge for several years. The battery 206 canprovide power to the sensor pod 200 for up to 10 years with an averageof 700 activation per hour, twenty four hours a day, every day of theweek and can be replaced as needed according to an embodiment of theinvention. In some embodiments, the battery life is up to 5 years.According to various embodiments of the present invention, the battery206 is electrically connected in parallel to one or more HLC capacitors208 to support high current operations. As understood by those skilledin the art, the HLC capacitor 208 also protects the battery 208 fromdegradation at transit power by reducing the load on the battery andthereby extends the life of the battery 206.

An embodiment of the sensor pod 200 has the capability to transmit at ahigh power of approximately 20 dBm to the access point 300. Together thecommunication controller 220 and vehicle detector controller 240 managethe power from the power source. The HLC capacitor 208 electricallyattached in parallel to the battery allows for high current draw whichsupports the high power radio transmissions. One or both of thecontrollers 220, 240 are adapted to detect the signal strength of areceived signal from the access point 300 and adjusting the transmittingpower based upon that strength such that power is conserved, therebylengthening battery life. An embodiment of the sensor pod 200, forexample, provides extended range features that allow the pod tocommunicate with the access point 300 without repeaters and with a longbattery life.

FIG. 5 illustrates an embodiment of the vehicle detector controller 240that is adapted to sense parameters for detecting vehicles, measuringvehicle occupancy, counting the number of detected vehicles, detectingparameters for speed calculations, and other parameters for a broadrange of transportation and traffic applications.

An embodiment of the vehicle detector controller 240 can include, forexample, a plurality of Anisotropic Magneto-Resistive based magneticsensors 212 a-d adapted to sense parameters of vehicles. Vehiclescontain ferrous materials that disturb the uniform intensity anddirection of the Earth's magnetic field. Embodiments of the sensor pods200 may include one or more magnetic sensors 212 to detect disturbancesof the Earth's magnetic field created by a vehicle (e.g., car, truck, ormotorcycle). In some embodiments, one or more of the plurality ofmagnetic sensors 212 may act as redundant sources of vehicle detectionin the event that a magnetic sensor fails. As illustrated in FIG. 5, thevehicle detector controller 240 may include a x-axis magnetic sensor 212a, a y-axis magnetic sensor 212 b, and a z-axis magnetic sensor 212 c.In certain embodiments, the vehicle detector controller 240 may includetwo z-axis magnetic sensors 212 c, 212 d spaced apart in a single sensorpod to calculate the speed of a passing vehicle. The dual sensors 212 c,212 d may also act as redundant sensors if one of the sensors fails tooperate properly. In other embodiments the dual magnetic sensors may betwo y-axis or x-axis sensors, or a combination of the x, y, or z-axissensors. With dual placed magnetic sensors, the first magnetic sensorwill experience a detection of the passing vehicle a fraction of asecond before the second sensor in moving traffic. With a predetermineddisplacement distance between two magnetic sensors and time measurementbetween the two magnetic sensors, a speed computation can be made usinga single sensor pod. In some embodiments, a plurality of sensor pods 200can be placed at a predetermined displacement distance and used tocalculate the speed of a passing vehicle. Speed computation can beperformed by the sensor module controller 230 in the vehicle detectorcontroller 240 or by one or more remote devices that receive data sensedby the sensor pod 200. The sensor module controller 230 can also receivesensed data from one or more temperature 215 and vibration 216 sensorsand process the sensed data to determine, for example, the presence ofice, snow, water or temperature measurements. Signal processingfunctions of the sensor module controller 230 may also includecharacterizing sensed vibrations data to facilitate the detection andclassification of a vehicle.

The sensor module controller 230 can further be adapted to determine ifone or more of the magnetic sensors 212 are operating withinsatisfactory limits and generate a signal or alarm if the one or moresensors are not operating satisfactory. This signal or alarm can bebased on historical measured values of the sensors. The signal or alarmcan be transmitted to the base station 400 or the traffic controller 402for further action by field personnel for example.

Embodiments of the vehicle detector controller 240 may also include acalibration module 213 adapted to adjust for sensor offset, or to set orreset one or more of the plurality of magnetic sensors 212. The vehicledetector controller 240 may also utilize one or more power controldevices such as MOSFETs 231 to intermittently supply power to differentcircuitry components including the plurality of magnetic sensors 212.According to an embodiment of the present invention, the output of theplurality of magnetic sensors 212 is routed through a differentialmultiplexer 214 and then passed to a fast respond differential amplifier217. The output of the amplifier 217 is routed to the sensor modulecontroller 230, which is adapted to perform signal processing accordingto an embodiment of the invention.

The sensor module controller 230 can process sensed data to determine,for example, the presence of a vehicle, count the number of detectedvehicles, and the speed of passing vehicles. In some embodiments, thesensor module controller 230 gathers the sensed data from the magneticsensors 212 and transmits the data for the base station 400, or trafficcontroller 402 to process the sensed data and determine the presence ofa vehicle and other traffic parameters. The sensor module controller 230can further include an analog to digital converter to convert the signalreceived from the differential amplifier 217 to digital information. Thesensor module controller 230 can be further adapted to communicate withthe communication controller 220, which is adapted to relay informationto and from the access point 300.

As illustrated in FIG. 6, the communication controller 220 can includeone or more of a radio transceiver 222, an antenna 204, a serial memory205, a communication module controller 210 and a MOSFET 231 or otherpower control device. According to an embodiment of the presentinvention, the communication controller 220 is adapted to receivesignals from the vehicle detector controller 240 and generate a packetsuitable to be wirelessly transmitted to the access point 300. Thecommunication controller 220 can also perform overhead functions for thesensor pod 200 including, for example, the timing and synchronization ofcommunicating data signals, and data formatting. One or more of theforegoing functions can be performed by the communication modulecontroller 210 according an embodiment of the present invention. Thecommunication module controller 210 can also receive sensed data fromone or more temperature 215 and vibration 216 sensor and process thesensed data to determine, for example, the presence of ice, snow, wateror temperature measurements. A serial memory 205, as understood by thoseskilled in the art, can also be used to facilitate remote firmwareupgrades to the sensor pods 200. The memory, according to an embodiment,is non-transitory and may store one or more computer programs to beexecuted by the communication module controller 210 or the sensor modulecontroller 230 for example.

The radio transceiver 222 of the communication controller 220 isconfigured to communicate in the 902-928 Mhz ISM band according to anembodiment of the invention. In other embodiments, the radio transceiver222 is configured to communicate in the 433-435 MHz ISM band, or boththe 433-435 MHz and the 902-928 Mhz ISM band for example. An operatingfrequency in the 902-928 Mhz ISM or 433-434 MHz ISM band provides agreater communication range than the operating frequency of 2.4 Ghz, forexample because the 2.4-2.5 Ghz ISB band typically has greater passlosses. Also, the airways of the 2.4-2.5 Ghz ISB band are more crowdedthan the 902-928 Mhz ISB because the 2.4-2.5 Ghz ISB band includes RFsignals from common devices such as Wi-Fi hubs, and Bluetooth devices. Acommunication frequency of no more than 928 Mhz provides sufficientlylow attenuation communication and range at the available power for thesensor pods according to embodiments of the invention. Althoughexemplary embodiments of the sensor pods 200 include one or more radiotransceivers 222 adapted to operate at a frequency at or less than 928Mhz, a 2.4 Ghz operating frequency is suitable for some components ofthe wireless vehicle system such as the radio communication between thebase station 400 and the access point 300.

Antenna size is inversely proportional to the frequency and therefore,as understood by those skilled in the art, the size of an antennaoperating at 900 Mhz is typically larger than an antenna operating at2.4 Ghz. Embodiments of the sensor pod 200 can include an antenna 204adapted to fit inside the enclosure of the sensor pod. The antenna 204can be low profile and adapted to be positioned in a substantiallyhorizontal orientation when positioned inside the enclosure of thesensor pod, as illustrated in FIG. 3 for example. The low profileantenna 204 can also have an antenna housing having a hollow interior toallow communication circuitry components to be mounted at leastpartially inside the antenna housing thereby decreasing vertical spacerequirements inside the enclosure of the sensor pod. In some embodimentsthe antenna 204 is a low profile loop antenna or a low profile patchantenna as understood by those skilled in the art.

Embodiments of the sensor pod 200 can include a non-transitory memoryhaving an executable program stored thereon to manage the power of thesensor pod. FIG. 13 illustrates an example embodiment of the instructionof a program loop executed by the sensor pod to manage power of thesensor pod. Both the vehicle detector and communication controllers 220,240 spend most of the time in a power-saving sleep mode. Powermanagement methods of embodiments of the invention enable the sensor pod200 to run for a number years without replacing the battery. The programloop instructions illustrated in FIG. 13 can be implemented on both thevehicle detector controller 240 and the communication controller 220individually and in combination. In step 802, for example, the sensorpod will go into a low power sleep mode 802 for a predetermined amountof time. When the sensor pod wakes up, in step 804, for example, thecontroller executes the next function and then schedules a subsequentfunction in the chain to be executed in step 806 for example. Accordingto an embodiment of the present invention, there is always one pendingevent or function to be executed by the sensor pod.

FIG. 14 example embodiment of the instruction of a program loop executedby the sensor pod to manage power of the sensor pod for an asynchronousevent being triggered on the communication controller 220 as understoodby those skilled in the art. In step 902, for example, the sensor podwill go into a low power sleep mode for a predetermined amount of timeor until an event is triggered. When an event is triggered 904, thesensor pod wakes up from the low power sleep mode and executes theasynchronous event in step 906, and schedules a subsequent function inthe chain to be executed in step 912. If an event is not triggered, suchas in step 910, the pod remains sleep for a predetermined amount of timeand then wakes up and executes the next function scheduled to beexecuted in step 910 and then schedules a subsequent function in thechain to be executed in step 912, for example. The above mentionedprogram loop implements an asynchronous event driven system for anembodiment of the wireless vehicle detection system and associatedmethods.

FIG. 7 illustrates a block diagram of an embodiment of an access point300 that is adapted to communicate with a plurality of sensor pods 200and a base station 400. A single access point 300 can communicate withup to 130 sensor pods according to an embodiment of the presentinvention. The wireless vehicle detection system can include the use ofa plurality of access points 300 at a traffic intersection. As user ofthe wireless vehicle detector system can map zones to include one ormore sensor pods and an access point 300. Embodiments of the accesspoint 300 may include a plurality of radio controllers 304 adapted tocommunicate with sensor pods 200 at an operating frequency ofapproximately 900 Mhz, and one or more base station communicationcontrollers 312 adapted to facilitate communication with the basestation 400 at an operating frequency at approximately 2.4 Ghz using anantenna 305. Each radio controller 304 can talk to multiple sensor pods200 using a low-power randomized-time-of-transmission TDMA protocol. Theaccess point 300 can communicate with the base station by wire orwirelessly. According to an embodiment of the access point 300, a Zigbeeradio module 312, as understood by those skilled in the art, is used tocommunicate wirelessly to the base station 400 and an RS-485 link, asunderstood by those skilled in the art, is used for wired communication.According to certain embodiments, all of the radio controllers 304 thatare in communication with the sensor pods 200 are kept synchronized bythe access point module controller 310. Synchronization allows the radiocontrollers to schedule transmission in the same time slots. This way,transmitting radios do not overload adjacent radio receivers. The accesspoint module controller 310 is adapted to collect data from theplurality of radio controllers 304, aggregate the data, and transmit thedata the base station 400 located in the traffic controller cabinetaccording to an embodiment of the invention.

Embodiments of the access point 300 may include one or more antennas301, 303, positioned remotely from an access point housing 302 asillustrated in FIGS. 8 and 10, for example. The one or more antennas301, 303 are adapted to be in communication with the plurality of sensorpods 200 and further adapted to communicate with the access pointhousing 302, which in turn communicates with the base station 400.

According to an embodiment of the present invention, the antenna can bean omnidirectional antenna 301, as understood by those skilled in theart, mounted to a traffic pole or mass arm at and within approximately300 feet of the plurality of sensor pods 200 and at the operatingfrequency of approximately 900 Mhz. FIG. 12 illustrates theomnidirectional antenna 301 according to an embodiment of the invention.For traffic intersections that may require the sensor pods 200 to beapproximately 300-700 feet from the access point 300, a combination ofan omnidirectional antenna 301 and panel antennas 303 can be used asillustrated in FIG. 10 for example. In an example embodiment, the panelantennas 303 can communicate with the sensor pods 200 positioned 300-700feet away and the omnidirectional antenna 301 can communicate with thesensor pods 200 positioned within 300 feet.

As illustrated in FIG. 11, according to an embodiment of the invention,the panel antenna 303 is a directional antenna with two panel antennasmounted a predetermined distance between each other and a polepositioned there between. One or more RF cables can be used tocommunicate data between the antennas 303, 301 and the access pointhousing 302. FIG. 9 illustrates an embodiment of the access pointhousing 302 according to an embodiment of the invention.

When selecting a mounting location for the access point 300, factors tobe considered may include the elevation needed for RF communications,the line of sight to the traffic controller cabinet 600, the distancefrom the wireless sensor pods 200, and the accessibly of the mountedaccess point to field support personnel using a lift truck. The antennas301, 303 can be mounted approximately 15-30 feet above ground, forexample, on a traffic pole or mast arm and adjacent to the access pointhousing 302. The access point housing 302 can be placed in the line ofsite and close to the traffic controller cabinet 600 that houses thebase station 400 according to an embodiment of the invention. When theaccess point and base station are communicating wirelessly, the accesspoint 300 can receive approximately 120 VAC from an interface panel inthe traffic controller cabinet 600 through a power cable connected therebetween. In other embodiments, the access point 300 receives power usingthe RS-485 link that is used for wired communication between the accesspoint 300 and the base station 400.

Each traffic region can utilize one or more sensor pods that make up azone. Each zone uses an access point 300 that is in communication withone or more sensor pods 200 according to an embodiment of the invention.The zones and sensors can be mapped using a graphical user interface(GUI), such as illustrated in FIG. 20 for example. The base station 400automatically detects the presences of sensors 200 and the GUI can beviewed on a remote device 407 to facilitate the mapping of the sensorsaccording to an embodiment of the invention. The interface can be viewedusing a web browser and can illustrate, for example, a sensor tree thatillustrates the organization of sensors, and details of individualsensors. As understood by those skilled in the art, such sensor detailscan include, for example, a sensor name, unique id, sensor description,the current mode, read right frequency, battery level, vehicle samplefrequency, sensitivity, and detect timeout.

In an embodiment of the invention, sensor information and processedsensor data can be viewed using the GUI using data processed by the basestation 400. The base station 400 has the computing power of an advancetransportation controller (ATC), as understood by those skilled in theart, and is adapted to provide data processing and storage of data for aplurality of sensor pods in a plurality of zones according to anembodiment of the invention. The base station can be connected to a LANor a WAN. In some embodiments, one or more web services are used onprivate networks to provide access to information relating to thewireless vehicle detector system 100.

As illustrated in FIG. 15, an embodiment of the base station 400 caninclude a base station controller 602, a base station communicationcontroller 604, an antenna 616 adapted to communicate in the 2.4-2.5 GhzISB band, and a synchronous data link control (SDLC) interface 614 asunderstood by those skilled in the art. The SDLC interface 614 can beused to connect to a traffic controller 402. Embodiments of theinvention include, for example, Bus Interface Units (BIU) to emulatedetector to the traffic controller 402. The base station communicationcontroller 604 can be adapted to facilitate communication with aplurality of access points 300. The base station controller 602 caninclude, for example, a traffic detector aggregator 610, detectoroutputs 612, and one or more BIU emulators 608. According to anembodiment, the base station is positioned near the top of the trafficcontroller cabinet 600 and an AC power cord is used to provide powerbetween the base station 400 and an interface panel in the cabinet 600as understood by those skilled in the art.

The base station can also include one or more non-transitory memoriesencoded with one or more computer programs operable by the base stationcontroller 602 according to an embodiment of the invention. The basestation can perform signal processing functions for the plurality ofsensors 200 in the wireless vehicle detection system 100. For example,according to an embodiment of the invention, the base station 400 canexecute one or more computer programs to analyze and interpret senseddata for counting the number of vehicles, occupancy, perform speedcalculation, and other roadway conditions.

FIGS. 16 and 7 illustrate an embodiment of the sensor state aggregator316 on or associated with an access point module controller 310. Thesensor state aggregator 316 maintains a sensor state array 360 in whicheach attached sensor pod 200 has an entry. These entries for sensor podscontain the current detect status for each sensor in a zone. Accordingto an embodiment of the invention, every message 351 sent by a sensorpod to the access point 300 contains the current detect status. Usingthis status, the sensor state array 360 is updated with every messagereceived and sent to the base station periodically or upon demand. Allof the individual status messages 361 are transferred to the basestation and may be responsive to an event trigger. The individual statusmessages 361 typically include a time stamp associated with the statuschange.

Embodiments of the invention can include, for example, a sensor stateaggregator 316 comprising a set of instructions that cause the accesspoint 300 to perform the operations when the instructions are executedby the access point module controller 310, for example. The operationsof the sensor state aggregator 316 associated with the access point caninclude, for example, generating a first sensor state array 360, each ofthe one or more sensor pods 200 in the respective zone having an entryin the sensor state array. The operations of the sensor state aggregator316 can further include, for example, updating the sensor state array360 responsive to receiving one or more signals from the one or moresensor pods 200 in the respective zone, the one or more signalsincluding current detect status of the one or more sensor pods, andcommunicating an output message indicating a time stamp and eventtrigger details responsive to receiving an individual status message 361from one or more of the sensor pods responsive to an event trigger. Theoperations of the sensor state aggregator 316 can further include, forexample, communicating the updated sensor state array indicating currentdetect status of the one or more sensor pods to the base station upondemand or periodically.

FIG. 17 illustrates an overview of a traffic detector aggregator 610 onor associated with the base station 400 according to embodiments of thepresent invention. The base station 400 receives the sensor state arraymessage 362, and individual sensor messages 361 from the access point.Based on the type of message, it is parsed and routed differently asunderstood by those skilled in the art. According to an embodiment ofthe invention, every message from sensor pod contains its detect statusbit, but only the dedicated detect status messages 360 contains the timestamp for the event as will be understood by those skilled in the art.The base station also maintains a sensor state array 370 (see e.g., FIG.18) that is similar to the sensor state array 360 associated with theaccess point 300. The sensor state array 370 associated with the basestation, in some embodiments, includes information indicating thecurrent detect status for all of the sensors 200 in the plurality ofzones. The traffic detector aggregator 610 can also maintain a vehicledetector array 380, which maintains the status of numerous, e.g., 64,physical detector inputs, along with a 16 bit time stamp of when thestatus changed last time. FIG. 19 illustrates an embodiment of thevehicle detector array 380. According to an embodiment of the vehicledetector array 380, the vehicle detector array maintains the detectorinputs and the time stamp information for a plurality of sensors in aplurality of zones.

Embodiments of the invention can include, for example, a trafficdetector aggregator 610 comprising a set of instructions that cause thebase station 400 to perform the operations when the instructions areexecuted by the base station controller 602, for example. Theinstructions of the traffic detector aggregator 610 associated with thebase station is adapted to aggregate data from the plurality of accesspoints in the plurality of zones so that a user can configure andmonitor the wireless vehicle detection system 100 according to anembodiment of the invention. The traffic detector aggregator 610 caninclude, for example, a set of instructions that cause the base station400 to perform operations such as, generating a sensor state array 370associated with the base station 400, each of the one or more sensorpods in all of the zones having an entry in the sensor state array 370.Embodiments of the invention can further include operations such asupdating the sensor state array 370 responsive to receiving updatedsensor state array 360 from one of the plurality of access points 300.Embodiments of the invention can also include, for example, generating avehicle detector array 380 comprising information indicating a physicaldetector input for each of the zones of and time stamps of eventtriggers, and updating the vehicle detector array 380 responsive toreceiving the output message from one of the plurality of access points300.

The sensor state arrays, traffic detector aggregator, and vehicledetector array maintained by the base station 400 and the access point300 can be implemented and maintained by electronic hardware, software,or a combination of the two as understood by those skilled in the art.

According to an embodiment, each zone is assigned a physical detectorbit in the vehicle detector array 380 and each BIU 608 is mapped to 16physical detector inputs. In an example embodiment, physical detectorbits 1-16 are controlled by BIU1, 17-32 are controlled by BIU2, and soon. According to an embodiment, a base station can emulate BIU's 1 to 4,in other embodiments it can emulate BIU's 1 to 8 as understood by thoseskilled in the art. According to an embodiment, the vehicle detectorarray 380 is updated with every message received from every sensor podin all of the zones and the physical detector status is changed based onthe user configured zone mapping. When the base station emulates a BIU608, it is adapted to respond to a request from the traffic controlleron the SDLC interface 614 as understood by those skilled in the art. Thetraffic controller can act as a master and requests data from the BIUperiodically.

An embodiment of a method to aggregate sensor data associated with anaccess point in a wireless vehicle detection system, for example, caninclude maintaining accurate detect status, volume and occupancy data ifcommunication to base station is interrupted so that accuracy of data isnot reduced by momentary disruptions or delays in communication to basestation 400 and packing communication data for greater transferefficiency. Together, these characteristics, among others, allow for theuse of a low-cost RF link, such as Zigbee. Use of a wirelesscommunication link between the access point 300 and the base station 400is more convenient and less costly to install than a wired link in manycases. Aggregation and combination of the sensor data into detect statesfor input to the controller 602 at the base station 400, for example,allows for combination of individual sensor states and data to becombined in different ways to generate intelligent vehicle detectioninputs and allows data to be formatted in different ways to supportmultiple interface methods to the controller. As understood by thoseskilled in the art, emulation of one or multiple BIUs 608, for example,allows for a simple and flexible way to transfer detection states to thecontroller and allows use of a pre-existing, standard interface (such asNEMA TS2) which, in turn, allows for ease of installation andconfiguration (e.g., only one serial cable connection is needed). Asappreciated by those skilled in the art, embodiments of the presentinvention allow for configurable single or multiple BIUs accommodatingdifferent equipment configurations in the cabinet assembly withoutadditional hardware assemblies, adapters, or multiple cables.

In the various embodiments of the invention described herein, a personhaving ordinary skill in the art will recognize that various types ofmemory are readable by a computer such as the memory described herein inreference to the various computers and servers, e.g., computer, computerserver, web server, or other computers with embodiments of the presentinvention. Examples of computer readable media include but are notlimited to: nonvolatile, hard-coded type media such as read onlymemories (ROMs), CD-ROMs, and DVD-ROMs, or erasable, electricallyprogrammable read only memories (EEPROMs), recordable type media such asfloppy disks, hard disk drives, CD-R/RWs, DVD-RAMs, DVD-R/RWs,DVD+R/RWs, flash drives, memory sticks, and other newer types ofmemories, and transmission type media such as digital and analogcommunication links. For example, such media can include operatinginstructions, as well as instructions related to the system and themethod steps described above and can operate on a computer. It will beunderstood by those skilled in the art that such media can be at otherlocations instead of, or in addition to, the locations described tostore computer program products, e.g., including software thereon. Itwill be understood by those skilled in the art that the various softwaremodules or electronic components described above can be implemented andmaintained by electronic hardware, software, or a combination of thetwo, and that such embodiments are contemplated by embodiments of thepresent invention.

This application is related to and claims priority and benefit toprovisional application No. 61/770,606, titled, “Wireless VehicleDetection System and Associated Methods Having Enhanced Response Time,”filed on Feb. 28, 2013; application No. 61/770,789, titled, “WirelessVehicle Detector Aggregator and Interface to Controller and AssociatedMethods,” filed on Feb. 28, 2013; and application No. 61/770,951, titled“Wireless Vehicle Detection System, Sensor Pods, and AssociatedMethods,” filed on Feb. 28, 2013, each of which is incorporated hereinby reference in its entirety.

In the drawings and specification, there have been disclosed embodimentsof the invention, and although specific teens are employed, the termsare used in a descriptive sense only and not for purposes of limitation.The invention has been described in considerable detail with specificreference to these illustrated embodiments. It will be apparent,however, that various modifications and changes can be made within thespirit and scope of the invention as described in the foregoingspecification, and such modifications and changes are to be consideredequivalents and part of this disclosure.

That is claimed:
 1. A wireless vehicle detection system comprising: oneor more spaced-apart sensor pods positioned in or below and yet in closeproximity to a plane of a surface of a road, adapted to detect receivedcommunication signal strength, and operationally adapted to adjusttransmitting power based upon said strength to thereby conserve powerusage, each sensor pod including (1) a vehicle detector controlleradapted to determine presence of one or more vehicles, (2) acommunication controller connected to the vehicle detector and adaptedto communicate data relating to the presence of one or more vehicles,the vehicle detector controller and the communication controller eachhaving separate clock cycles and separately controlled sleep cycles fordrawing power, (3) a battery sufficiently large to support transmitrange by the pod of 300 feet or more, (4) a hybrid layer capacitorconnected in parallel electrically to the battery to protect the batteryfrom degradation at transmit power levels and extend the life of thebattery; and (5) a low profile antenna positioned in a substantiallyhorizontal orientation when positioned inside an enclosure of the sensorpod and near a top end of the enclosure when the sensor pod ispositioned in or below the surface of the road, the antenna adapted toallow for and support 902-928 MHz ISM radio frequency band, the lowprofile antenna also having an antenna housing having a hollow interiorto allow communication circuitry components to be mounted at leastpartially inside the antenna housing thereby decreasing vertical spacerequirements inside of the enclosure of the sensor pod; a base stationadapted to provide data processing and storage for the wireless vehicledetection system; and an access point adapted to communicate with thebase station wireless at a communication frequency of approximately 2.4GHz or via one or more wires, and further adapted to communicate withthe one or more sensor pods at a communication frequency ofapproximately 902-928 Mhz.
 2. The system of claim 1, wherein the vehicledetector controller is adapted to communicate with the communicationcontroller, the vehicle detector controller further comprising: aplurality of magnetic sensors adapted to sense the presence of one ormore vehicles, and to output sensed data corresponding to the presenceof one or more vehicles; a calibration module adapted to adjust forsensor offset, or to set or reset the plurality of magnetic sensors; anda sensor controller adapted to determining the presence of the one ormore vehicles responsive to one or more of the plurality of magneticsensors outputting the sensed data.
 3. The system of claim 1, whereinthe communication controller is adapted to communicate with the vehicledetector controller via a serial link, the communication controllerfurther comprising: a radio transceiver adapted to communicate in the902-928 Mhz ISM band; the antenna; and a communication controlleradapted to generate a packet suitable to be wirelessly transmitted viathe antenna to the access point.
 4. The system of claim 1, wherein thevehicle detector controller is adapted to communicate with thecommunication controller, the vehicle detector controller furthercomprising: a plurality of magnetic sensors adapted to sense thepresence of one or more vehicles, and to output sensed datacorresponding to the presence of one or more vehicles; a calibrationmodule adapted to adjust for sensor offset, or to set or reset theplurality of magnetic sensors; and a sensor controller adapted todetermining the presence of the one or more vehicles responsive to oneor more of the plurality of magnetic sensors outputting the sensed data;and wherein the communication controller further comprises: a radiotransceiver adapted to communicate in the 902-928 Mhz ISM band; theantenna; and a communication controller adapted to generate a packetsuitable to be wirelessly transmitted via the antenna to the accesspoint.
 5. The System of claim 1, wherein the access point furthercomprises a plurality of antennas, one or more first antennas of theplurality of antennas being adapted to communicate with the base stationat approximately 2.4 GHz and one or more second antennas of theplurality of antennas being adapted to communicate with the one or moresensor pods at approximately 902-928 Mhz.
 6. The system of claim 1,wherein the access point comprises an access point housing and anomnidirectional antenna adapted to be positioned remote from the accesspoint housing, the omnidirectional antenna adapted to wirelesscommunicate with the one or more sensor pods and to communicate with anantenna associated with the access point housing.
 7. The system of claim1, wherein the vehicle detector controller comprises a plurality ofmagnetic sensors adapted to sense the presence of one or more vehicles,and to output sensed data corresponding to the presence of one or morevehicles.
 8. The system of claim 7, wherein the plurality of magneticsensors include at least one of an x-axis sensor, a y-axis sensor, and az-axis sensor.
 9. A wireless sensor pod adapted to be positioned in orbelow and yet in close proximity to a plane of a surface of a road, thesensor pod comprising: (1) a vehicle detector controller adapted todetermine presence of one or more vehicles; (2) a communicationcontroller adapted to detect received communication signal strength andoperationally adapted to adjust transmitting power based upon saidstrength to thereby conserve power, the communication controller furtheradapted to transmit data 300 feet or more; (3) a battery sufficientlylarge to support transmit range by the communication controller of 300feet or more, (4) a hybrid layer capacitor connected in parallelelectrically to the battery to protect the battery from degradation attransmit power levels and extend the life of the battery; and (5) aantenna positioned in a substantially horizontal orientation whenpositioned inside the sensor pod and when the sensor pod is positionedin or below the surface of the road, the antenna adapted to allow forand support 902-928 MHz ISM radio frequency band, the antenna alsohaving an antenna housing having a hollow interior to allowcommunication circuitry components to be mounted at least partiallyinside the antenna housing thereby decreasing vertical spacerequirements inside of the enclosure.
 10. The sensor pod of claim 9, thecommunication controller further comprising: a radio transceiver adaptedto communicate in the 902-928 Mhz ISM band; the antenna; and acommunication controller adapted to generate a packet suitable to bewirelessly transmitted via the antenna to an access point.
 11. Thesensor pod of claim 9, the vehicle detector controller furthercomprising: a plurality of magnetic sensors adapted to sense thepresence of one or more vehicles, and to output sensed datacorresponding to the presence of one or more vehicles; a calibrationmodule adapted to adjust for sensor offset, or to set or reset theplurality of magnetic sensors; and a sensor controller adapted todetermining the presence of the one or more vehicles responsive to oneor more of the plurality of magnetic sensors outputting the sensed data;and wherein the communication controller further comprises: a radiotransceiver adapted to communicate in the 902-928 Mhz ISM band; theantenna; and a communication controller adapted to generate a packetsuitable to be wirelessly transmitted via the antenna to the accesspoint.
 12. A sensor pod of claim 9, wherein the one or more sensor podsfurther comprises a non-transitory computer readable storage mediumhaving an executable program stored thereon, and one of the vehicledetection controller or the communication controller is adapted toexecute the executable program to wake up the sensor pod from sleep modeto execute a function and to queue a next function to be subsequentlyexecuted.
 13. An access point adapted to provide communication betweenone or more sensor pods and a base station, the access controlcomprising: one or more first antennas adapted to communicate with oneor more remote sensor pods of a wireless vehicle detection system at afrequency of approximately 902-928 MHz; one or more second antennasadapted to communicate with a remote base station of the wirelessvehicle detection system at a frequency of approximately 2.4 GHz.
 14. Aaccess point of claim 13, one or more access point controllers adaptedto synchronize communication with the one or more remote sensor pods,the access point controller further adapted to relay information to thebase station or the one or more remote sensor pods according torandomized-time-of transmission TDMA protocol.
 15. A method fordetecting one or more vehicles, the method comprising the steps of:installing a sensor pod in or below and in close proximity to a plane ofa surface of a road, the sensor pod adapted to detect and receivecommunication signal strength and operably adapted to adjusttransmitting power based upon said strength to thereby conserve power,the sensor pod including (1) a vehicle detection controller adapted todetermine presence of one or more vehicles, (2) a communicationcontroller adapted to communicate data relating to the presence of oneor more vehicles, (3) a battery, (4) a hybrid layer capacitor connectedin parallel electrically to the battery to protect the battery fromdegradation at transmit power levels, and (5) an antenna positioned in asubstantially horizontal orientation when positioned inside the sensorpod and when the sensor pod is positioned in or below the surface of theroad, the antenna adapted to allow for and support 902-928 MHz ISM radiofrequency band, the antenna also having an antenna housing having ahollow interior to allow communication circuitry components to bemounted at least partially inside the antenna housing; transmitting datarelating to the presence of one or more vehicles from the sensor pod toan access point positioned remote the sensor pod; and providing dataprocessing to a traffic controller by a base station positioned remotefrom the access point and the sensor pod, the data processing beingresponsive to the base station receiving data from the access point. 16.A method of claim 15, wherein the access control comprises: one or morefirst antennas adapted to communicate with the sensor pod at a frequencyof approximately 902-928 MHz; one or more second antennas adapted tocommunicate with the base station of the wireless vehicle detectionsystem at a frequency of approximately 2.4 GHz.
 17. A method of claim15, wherein the vehicle detector controller comprises a plurality ofmagnetic sensors adapted to sense the presence of one or more vehicles,and to output sensed data corresponding to the presence of one or morevehicles.
 18. A method of claim 15, wherein the vehicle detectorcontroller further comprising: a plurality of magnetic sensors adaptedto sense the presence of one or more vehicles, and to output sensed datacorresponding to the presence of one or more vehicles; a calibrationmodule adapted to adjust for sensor offset, or to set or reset theplurality of magnetic sensors; and a sensor controller adapted todetermining the presence of the one or more vehicles responsive to oneor more of the plurality of magnetic sensors outputting the sensed data.19. A method of claim 15, wherein the communication controller furthercomprising: a radio transceiver adapted to communicate in the 902-928Mhz ISM band; the antenna; and a communication controller adapted togenerate a packet suitable to be wirelessly transmitted via the antennato the access point.
 20. A method of claim 15, wherein the vehicledetector controller and the communication controller each havingseparate clock cycles and separately controlled sleep cycles for drawingpower.